High-pressure reciprocating compressor



Nov. 25,1930. c. SCHAER 1,782,975

HIGH PRESSURE REGIPROGATING COMPRESSOR Filed Sept. 29, 1928 2 Sheets-Sheet 1 Nay. 25, 1930. c. SCHAER 3 HIGH PRESSURE REGIPROCATING' COMPRESSOR Filed Sept. 29, 1928 2 Sheets-Sheet 2 EV @w XML )nwf Ari El F\N 5% Patented Nov. 25, 71930 UNITED. STATES CHARLES: SCHA'ER, or LANGENTHAL, SWITZERLAND, AssIeNonmornE rum or PATENT OFFICE soLzER FRERES socn'iri'e ,ANONYME, or WINTERTHUR, S ITZERLAND.

HIGH-PRESS RE nEoIrRocATinG 'ooMrREssoR Application filed September 29, 1928,:Seria1 No.

This invention relates to high pressure reciprocating compressors of the kindinwhich power is transmitted'from the piston of-the driving machine through an oscillating column of liquid to ani nterinediate or driving piston which actuates the compressor piston.

According to the present invention in a compressor of the kinddescribedmeans are provided for rendering inoperative a portion of the liquid column so as to varythe length of the stroke of the compressor piston or pistons without changing the "mid point about a which such compressor pistons reciprocate.

Preferably the portion of the liquid column to be renderedlinoperative is diverted through a bypass pipe into a chamber in which it transmits nopower. Both the intermediate piston and the piston of the driving machine may be inthe form of double-acting stepped pistons, corresponding liquid columns on ope posite sides of these pistonsbeing connected by by-pass pipes. Alternately,either of these pistons may be a simple double-acting piston a and the other a stepped piston. ,The conduits provided with stop valves 'toeontrol the pasand by-pass pipes for the liquid columns are sage of the liquid and those stopfvalves which are to be opened orclosedsimultaneously may be prov ded wlth a; common control mecha- The invention may be carried out in various ways but three arrangements, accord1ng thereto are illustrated by way of example as C applied to atwo-stage compressor in theaccompanying drawings in which @Figure 1 shows the position ofthe stop valves to produce the maximum length of i stroke of the compressor pistons, this[ length stroke,

strokes.

of stroke being indicated by the dotted end positions oflthe pistons, a

Figures 2 and 3 illustrate the-positions of the valves necessary to produce a shorter Figures 4; and 5 show modifications otthe arrangement illustrated in Figures 1-3, and

Figure 6 is a diagram of lengths of piston In the arrangement otFigures 1, 2 and 3,

i the double-acting double stepped piston 7 of the drivingmachine is adaptedto reciprocate coaasa na iii Switzeflandjlq'ovember 8, 15271 1 within-a cylinder 1 andRthereby to impartv oscillatory movement toa liquid columndividedintofour parts 2, 3, 4and 5'dispos'ed I within the cylinder; Theintermediate piston 13 reciprocates within its cylinder l2and is mounted on a piston rod 18 on which are also mounted the-compressor pistons20 and 22-weciprocating respectively within the-cylinders 19 and 21 of the stagesI' and II The liquid columns 2 and 3 are connectedby means of conduits 8 and 9 with one end of the inter mediate c'ylinder 12 while the columns 4 and 5 are connected by means of conduitsl and 15 mon controlrod 27. Similarly the simultae neous operation of the stop valves ll and-16 may be eflected 'bymeans ofa common control rod 28.

Assuming thatthe valves 1O, 11, 16, 17, 23 and 26 are inthe positions shown in Figure1,'-the operation of the apparatus is *as follows. v i Q 1 The working surface E of the piston 7 of the driving machine, for, each direction of motion, comprises thesmaller surface f and the larger surface f When the piston 7 movestowardsthe left in Figurel, the surfaces f and f act respectively on the liquid columns 2 and 3 and force them through the conduits 8 and 9into the left-hand end of the cylinder 12 thus forcing the intermediate piston 13 towardsthe right and effecting the compression of the medium'within therighthand ends of the cylinders 19 and 21. On the return stroke-otthe piston 7 1 the same" area3F%f +f acts on the liquid columns {1 e and 5 and forces themthrough the conduits 14 and 15 respectively intofithe right-hand .end of the cylinder "12 thus eflectingthe com pression of the medium within the left-hand ends of the cylinders 19 and 21. As can be seen from Figure 1, the stop valves 23 and 26 in the by-pass pipes 24 and are closed and the length of the stroke of the compressor pistons 20 and 22 is at a maximum.

If now it is desired to reduce the length of the stroke of the compressor pistons the efiective volume of the liquid column must be reduced, that is a part of the liquid column must be rendered inoperative. To this end the stop valves 10 and 17 are brought into the closed position shown in Figure 2 and the valve 23 opened, thus rendering the surface f and the columns 2 and 5 ineffective. With the valves in this position movement of the piston 7, for example towards the left in Figure 2, forces the liquid column 3 through the conduit 9 and valve 11 into the left-hand end of the cylinder 12. On the other hand, the liquid displaced by the surface f merely flows through the by pass pipe 24 into the space occupied by the column 5 anddoes no work on the intermediate piston 13. Consequently the piston 13 is only displaced as far as the end positions indicated in dotted lines in Figure 2.

On the return stroke of the piston 7 a similar action takes place, the reduction in the length of the stroke of the compressor pistons being equal to s in each direction, that is the total reduction equals 2X80, while the mid point about which the compressor pistons reciprocate remains unchanged. 7

If it is desired to reduce the length of the stroke still further the surface f of the piston 7 may be rendered ineffective by closing the valves 11, 16 and 23 and opening the valves 10, 17 and 26 thus putting the liquid columns 3 and 4 out of action (Figure 3). This reduces the length of the stroke of the compressor pistons to the dimensions inclicated by the dotted lines in Figure 3.

In the modified arrangement illustrated in Figure 4, the piston 7 of the driving machine is a simple double-acting piston while the intermediate piston 13 is in the form of a double-acting stepped piston. The piston 7 only acts on two, instead of four, liquid columns, that is the columns 30 and 31 of which the column 30 acts through aconduit 32 on the smaller right-hand surface of the piston 13 and through a conduit 33 on the larger right-hand surface thereof while the column 31 acts through conduits 36 and 37 on the smaller and larger left-hand ,surfaces respectively of the. piston 13. The conduits 32, 33, 36 and 37 are provided with stop valves 34, 35, 38 and 39 respectively and the two ends of the cylinder 12 of smaller diameter are connected by a by-pass pipe 40 while the ends of the larger cylinder 12 are connected by a by-pass pipe 41. These by-pass pipes are provided with stop valves 42 and 43 respectively. The valves 34, 38 and 42 may be operated by a common control mechanism as also may the valves 35, 39 and 43.

In order that a variation in the length of stroke of the compressor piston may be rendered possible, the dimensions of the areas and strokes of the pistons 7 and 13 are such that the length of the stroke of the compressor pistons 20 and 22 is greatest when the columns 30 and 31 act on the smallest surface of the intermediate piston 13, that is when the conduits 32 and 36 and the bypass pipe 41 are open, the conduits 33, 37 and 40 being closed (Figure 4). V

In the drawing (Figure 4) the larger sur face of the piston 13 has twice the area of the smaller surface so that in order to reduce the length of the stroke of the pistons 20 and 22 to one-half the columns 30 and 31 must act on the larger surface alone, the smaller surface being rendered inoperative. Again, if the length of the stroke is to be reduced to one-third of the maximum value the columns 30 and 31 mustbe made to act on the larger as well as on the smaller surface of the piston 13. Thus to reduce the stroke to onehalf thevalves 34, 38 and 43 must he closed and the valves 35, 39 and 42 open, while to reduce the length of the stroke to one-third of the maximum the valves 34, 35, 38 and 39 must be opened and the valves 42 and 43 closed.

The variation in the length of the stroke may be further graduated by making both the intermediate piston and the piston of the driving machine in the form of stepped pistons, the number of variations being dependent upon the number of steps. An example of an apparatus constructed in this way is illustrated diagrammatically in Figure 5.

In this arrangement both the liquid columns 2 and 3 are in communication with each of the intermediate cylinder spaces 45 and 46 while the columns 4 and 5 are both in communication with each of the intermediate cylinder spaces 47 and 48, the individual. conduit connections meeting at 49 and 50 as shown. These conduits are controlled by stop valves 51, 52, 53, 54 and 55, 56, 57 and 58 which are arranged as shown in the figure. In addition, the cylinder spaces 45 and 48 are connected by a by-pass pipe 40 while the spaces 46 and 47 are connected by a bypass pipe 41, these by-passes being provided with stop valves 42 and 43 respective] y. The ;r

cylinder spaces 2, 5 and 3, 4 are similarly connected by by-pass pipes 24 and 25 respectively, these by-passes being provided with stop valves 23 and 26 respectively.

The pistons 7 and 13 are so dimensioned 2L1:-

that the length of the stroke of the (0211- pressor pistons 20 and 22 is at a maxinnnn when the larger and smaller surfaces of the piston 7 displace the liquid columns 2 and 3 simultaneously and cause them both to act on the smaller surface of the piston 13 alone.

' To bring this about the valves 51, 52., 53, 55,

56, 58 and 43 must be opened and the valves 23, 26, 42, 54 and 57 closed. Conversely, the

length of the stroke of the pistons 20 and 22 is at a minimum when'theliquid column 2 alone is displaced into both the spaces 45 and 46in one direction and the column 5 alone is displaced into both the spaces 47 and 48 in the other direction, while the columns 3 and. 4 oscillate in the bypass without transmitting power. To effect this the valves mustbe in the positions shown in Figure 5.

It will be appreciated that the invention provides a number of possibleways of varying the length of the stroke of the compressor pistons without changing the mid point about which these pistons reciprocateg Thus, for example, the arrangement may be such that only a part of the liquid displaced by the piston of the driving machine acts on the intermediate piston while the remainder oscillates in a bypass pipe Without transmitting power (Figures 1-3). Alternatively,'the whole of the'liquid'displaced by the piston of the driving machine may be made to act on the intermediate piston and the V variation in stroke may be obtained by altering the Volume of the intermediate cylinder (Figure 4). Again, the liquid column actuated by the piston of the driving machine may be divided into a number of part columns, and the length of stroke varied by putting one or more of these columns out of action, and also by varying the volume of the cylinder containing the intermediate piston on which these columnsact (Figuree). As shown in Figure 6, themaximum length of stroke a of the compressor'pistons can be thus reduced to values such as s 8 etc. without changing the mid-point m about which these pistons reciprocat ing engineand the intermediate piston, said connection having a liquid column therein,

and means for rendering inoperative a portion of the said liquid column on occasion.

2. A compressor-plant, comprising a reciprocating-piston compressor, a driving engine having a cylinder and a reciprocating piston, another piston intermediate the engine and the compressor and structurally connected to the compressor piston, a cylinder therefor, a fluid-conduit between the piston of the driving engine and the intermediate piston,

i said connection having a liquid column therein, and a by-pass pipe in sald engine connected to said-liquid columnand having means for diverting a portion ofthe liquid column out ofqcommunication with said intermediate piston. a

I 3. Acompressor-plant, comprising a reciprocating-piston compressor, a driving engine havmga cyhnder and a double acting stepped reciprocating piston, another p ston L intermediate the engine and the compressor and structurally connected to the compressor piston, acylinder therefor, liquid columns in the respective cylinderson both sides of said driving engine piston and said intermediate piston, andrespective by-pass conduits connected onfltherespective stepped ends of said 1 stepped piston, said by-pass'es having means by which the respective columns of liquid can be shunted asdesired ,on'occasion.

*4. A compressor-plant, comprising a reciprocating-piston,compressor, a driving en gine having a cylinder and a double-stepped double acting, piston therein, a double-acting piston connected intermediate the compressor and engine to the compressor pistons, a cylinder therefor,-liquid containers inserted be-,

tween the piston of thedriving engine and the intermediate piston, and by pass pipes connecting correspondmg llq'uid columns on opposite sides of the said pistons.

i .5. A compressor-plant, compr1s1ng a reciprocat1ng-p1ston compressor, a drlvlng engine having a cylinder and areciprocating piston, another piston intermediate" the engine and the compressor and structurally connectedfto the compressor fpiston, a cylinder therefor,

a fluidaconduitbetweenthe piston of the driv; ing engine and the intermediate piston, said connection having a liqu'id celumntherein,

and a bypass pipe in said engine connected to said liquid column andhaving means for diverting a portion of the liquid column out of communication with said intermediate piston, said means comprising a stop-valve,

in said pipe. a i

6; A compressor-plant, compr sing a reciprocating-piston compressor, a driving engine having a cylinder and a double acting stepped reciprocating piston, another piston intermediate the engine-and the compressor and structurally connected to the. compressor a piston, acylinder therefor, liquid columns in the respective cylinders on both sides of said driving engine piston and said intermediate piston and respective by-pass conduits con nected on the respective stepped ends of said stepped piston, saidby-passes having means by which therespective columns of liquid canbe shunted as desired on occasion, said means comprising stop-valves therein on opposite sides of the stepped driving-engine pistonthrough vwhich the liquidican be respectively passed on occasion.

Q7. A compressonplant, comprising a reciprocating-piston compressor,a driving engine having a cylinder and a double acting stepped reciprocating piston, another piston intermediate the engine and the compressor and structurally connected to the compressor piston, a cylinder therefor, liquid columns in the respective cylinders 011 both sides of said driving engine piston and said intermediate piston, and respective by-pass conduits connected on the respective stepped ends of said stepped piston, said by-passes having means by which the respective columns of liquid can be shunted as desired on occasion, said means comprising stop-valves therein, said stop-valves being arranged to connect corresponding liquid columns on opposite sides of the intermediate and driving-engine pistons.

8. A compressor-plant, comprising a reciprocating-piston compressor, a driving engine having a cylinder and a double acting stepped reciprocating piston, another piston intermediate the engine and the compressor and structurally connected to the compressor piston, a cylinder therefor, liquid columns in the respective cylinders on both sides of said driving engine piston and said intermediate piston, and respective by-pass conduits connected on the respective stepped ends of said stepped piston, said by-passes having means by which the respective columns of liquid can be shunted as desired on occasion, said means comprising stop-valves therein, said stopvalves being arranged to connect corresponding liquid columns on opposite sides of the intermediate and driving-engine pistons, and means for simultaneously controlling said stop-valves.

In testimony whereof I have afixed my signature.

CHARLES SCHAER. 

